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Michael Wesbrook Staude, David A Leonard, Jeffrey W Peng
Gram-negative bacteria resist β-lactam antibiotics primarily by deploying β-lactamase proteins that hydrolytically destroy the antibiotics. In clinical settings, these bacteria are producing variant β-lactamases with "gain of activity" mutations that inactivate a broader range of β-lactams. Learning how these mutations broaden substrate activity is important for coping with β-lactam resistance. Here, we investigate a gain of activity mutation in OXA-24/40, a carbapenem-hydrolyzing Class D β-lactamase (CHDL) in Acinetobacter baumannii...
October 26, 2016: Biochemistry
Xin He, Chang Fei Duan, Yong Hua Qi, Jun Dong, Geng Nan Wang, Guo Xian Zhao, Jian Ping Wang, Jing Liu
In this study, an anti-amoxicillin single chain variable fragment (ScFv) antibody was evolved by directional mutagenesis of a contact amino acid residue based on the analysis of virtual mutation. Comparison with its parental ScFv, the mutant showed highly improved affinity for 11 penicillins with up to 6-folds increased sensitivity. Then, its recognition mechanisms for the 11 drugs were studied by using molecular docking. Results showed that the mutant-penicillins intermolecular forces increased and the total binding energies decreased dramatically, which were responsible for the improvement of antibody sensitivity...
October 22, 2016: Analytical Biochemistry
José A Cornejo-García, Abderrahim Oussalah, Miguel Blanca, Rosa-María Guéant-Rodríguez, Cristobalina Mayorga, Julie Waton, Annick Barbaud, Francesco Gaeta, Antonino Romano, Jean-Louis Guéant
Our knowledge of genetic predisposing factors of drug hypersensitivity reactions (DHRs) is still scarce. The analysis of the genetic basis of these reactions may contribute to dissect the underlying mechanisms. We will outline current knowledge of the genetic predictors of most common DHRs, including reactions to betalactam antibiotics (BLs), nonsteroidal anti-inflammatory drugs (NSAIDs) and biological agents. The predictors of DHRs to BLs are mostly linked to IgE-class switching, IgE pathway and atopy (IL4R, NOD2, LGALS3) in replicated candidate gene studies, and to antigen presentation (HLA-DRA) in the single replicated GWAS performed so far...
September 27, 2016: Current Pharmaceutical Design
Wei Li, Xiu-Jun Yin, Hua-Ying Liu, Rong Yang
INTRODUCTION: Syphilitic aortic aneurysm (SAA) is caused by tertiary stage of syphilis infection. As the wide application of penicillin, this complication is becoming rarer than before. The SAA with lung cancer is a very rare disease in patient. CASE DESCRIPTION: A 55-year-old male was admitted to the hospital complaining "progressive hoarseness for 3 months" and the patient has been diagnosed with syphilis after specific blood exams, computed tomography angiography (CTA) and 3dimensional (3D) reconstructions of cardiac vessels...
2016: SpringerPlus
Chunyapuk Kukusamude, Joselito P Quirino, Supalax Srijaranai
A coacervative extraction (CAE) with the common cationic surfactants dodecyltrimethylammonium bromide (DTAB) and didodecyldimethylammonium bromide (DDAB) was firstly developed. Notable characteristics of the CAE was the use of low concentration of salt (0.1molL(-1) NaBr) at ambient temperature and without the requirement of organic solvent. The CAE was based on phase separation due to the neutralization of the surface charge of the micelle by electrostatic interaction with the predominant common counter ion (bromide)...
October 12, 2016: Journal of Chromatography. A
Timothy K Lee, Kevin Meng, Handuo Shi, Kerwyn Casey Huang
The peptidoglycan cell wall is an integral organelle critical for bacterial cell shape and stability. Proper cell wall construction requires the interaction of synthesis enzymes and the cytoskeleton, but it is unclear how the activities of individual proteins are coordinated to preserve the morphology and integrity of the cell wall during growth. To elucidate this coordination, we used single-molecule imaging to follow the behaviours of the two major peptidoglycan synthases in live, elongating Escherichia coli cells and after perturbation...
October 24, 2016: Nature Communications
Travis E Wright, K Keely Boyle, Thomas R Duquin, John K Crane
BACKGROUND: Many studies have noted an increase in the number of recognized cases of invasive infections due to Propionibacterium acnes, especially after shoulder replacement surgery. The increase in the number of recognized cases of P. acnes, a nonspore-forming, anaerobic, Gram-positive organism, appears due to both an increase in the number of shoulder operations being performed and more specimens being sent for anaerobic cultures. Nevertheless, the optimal surgical and antibiotic management of P...
2016: Infectious Diseases
Kazufumi Kasuya, Tilusha Manchanayake, Kei Uenoyama, Sayaka Kawa, Kou Takayama, Naoto Imai, Tomoyuki Shibahara
An imported crossbred Angus beef steer aged eight to twelve months died suddenly on the eighth day of a quarantine period in Japan. Gross examination showed the peritoneum and mesentery consisted of numerous nodules of various sizes. Histological examination revealed chronic suppurative granulomatous peritonitis with eosinophilic rosettes surrounding colonies of Gram-negative bacilli. The bacteria isolated from the nodules were confirmed to be Actinobacillus lignieresii based on the results of 16S rRNA gene sequencing and immunohistochemistry...
October 21, 2016: Journal of Veterinary Medical Science
Worawut Choeyprasert, Suradej Hongeng, Usanarat Anurathapan, Samart Pakakasama
Bacteremia during neutropenic episodes is a cause of morbidity and mortality in patients undergoing hematopoietic stem cell transplantation (HSCT). We have used oral ciprofloxacin and penicillin V, from the start of the conditioning regimen until engraftment, for the prophylaxis of bacterial infection. The objective of this study was to retrospectively analyze the prevalence of and risk factors for breakthrough bacteremia during neutropenic episodes in autologous and allogeneic HSCT patients. There were 215 patients enrolled, with a median age of 8...
October 22, 2016: International Journal of Hematology
Dong Wang, Limei Zhang, Xuezhang Zhou, Yulong He, Changfu Yong, Mingliang Shen, Otto Szenci, Bo Han
Staphylococcus aureus is the leading pathogen involved in bovine mastitis, but knowledge about antimicrobial resistance, virulence factors, and genotypes of Staphylococcus aureus resulting in bovine mastitis in Ningxia, China, is limited. Therefore, antimicrobial susceptibility, virulence gene, and randomly amplified polymorphic DNA (RAPD) analyses of Staph. aureus were carried out. A total of 327 milk samples from cows with clinical and subclinical mastitis in 4 regions of Ningxia were used for the isolation and identification of pathogens according to phenotypic and molecular characteristics...
October 19, 2016: Journal of Dairy Science
Alexander Mischnik, Philipp Baumert, Axel Hamprecht, Anna Rohde, Silke Peter, Susanne Feihl, Johannes Knobloch, Hanna Gölz, Axel Kola, Birgit Obermann, Christiane Querbach, Matthias Willmann, Friedemann Gebhardt, Evelina Tacconelli, Petra Gastmeier, Harald Seifert, Winfried V Kern
As part of the multicenter Antibiotic Therapy Optimisation Study-the largest study on the prevalence of third-generation cephalosporin-resistant Enterobacteriaceae carriage upon hospital admission-minimum inhibitory concentration values were generated for ampicillin/sulbactam, amoxicillin/clavulanic acid, piperacillin/tazobactam, mecillinam, mecillinam/clavulanic acid, and temocillin against third-generation cephalosporin-resistant Escherichia coli, Klebsiella species and Enterobacter species.
September 23, 2016: Diagnostic Microbiology and Infectious Disease
Qiaohui Luo, Neng Yu, Chunfei Shi, Xiaoping Wang, Jianmin Wu
A surface plasmon resonance (SPR) sensor combined with nanoscale molecularly imprinted polymer (MIP) film as recognition element was developed for selective detection of the antibiotic ciprofloxacin (CIP). The MIP film on SPR sensor chip was prepared by in situ photo-initiated polymerization method which has the advantages of short polymerization time, controllable thickness and good uniformity. The surface wettability and thickness of MIP film on SPR sensor chip were characterized by static contact angle measurement and stylus profiler...
December 1, 2016: Talanta
Shanshan Wang, Yinjuan Guo, Jingnan Lv, Xiuqin Qi, Dan Li, Zengqiang Chen, Xueqing Zhang, Liangxing Wang, Fangyou Yu
BACKGROUND: Quinupristin/dalfopristin (Q/D) is a valuable alternative antibiotic to vancomycin for the treatment of multi-drug resistant Enterococcus faecium infections. However, resistance to Q/D in E. faecium clinical isolates and nosocomial dissemination of Q/D-resistant E. faecium have been reported in several countries and should be of concern. RESULTS: From January 2012 to December 2015, 911 E. faecium clinical isolates were isolated from various specimens of inpatients at the first Affiliated Hospital of Wenzhou Medical University located in Wenzhou, east China...
October 21, 2016: BMC Microbiology
Jean-Emmanuel Hugonnet, Dominique Mengin-Lecreulx, Alejandro Monton, Tanneke den Blaauwen, Etienne Carbonnelle, Carole Veckerlé, Yves Brun, Michael van Nieuwenhze, Christiane Bouchier, Kuyek Tu, Louis B Rice, Michel Arthur
The target of β-lactam antibiotics is the D,D-transpeptidase activity of penicillin-binding proteins (PBPs) for synthesis of 4→3 cross-links in the peptidoglycan of bacterial cell walls. Unusual 3→3 cross-links formed by L,D-transpeptidases were first detected in Escherichia coli more than four decades ago, however no phenotype has previously been associated with their synthesis. Here we show that production of the L,D-transpeptidase YcbB in combination with elevated synthesis of the (p)ppGpp alarmone by RelA lead to full bypass of the D,D-transpeptidase activity of PBPs and to broad-spectrum β-lactam resistance...
October 21, 2016: ELife
Eileen Hoskin, Analia Veitz-Keenan
Data sourcesCochrane Oral Health Group's Trials Register, the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, Clinical and the WHO International Clinical Trials Registry Platform. There were no language restrictions.Study selectionRandomised controlled trials which compared the relief of pain with systemic antibiotics and analgesics against placebo and analgesics in the preoperative phase of irreversible pulpitis. The primary interest was pain control with an antibiotic or without one in the presence of analgesics...
September 2016: Evidence-based Dentistry
Corinne Ruppen, Laurent Decosterd, Parham Sendi
BACKGROUND: According to expert opinions, gentamicin should be administered as an adjunct to penicillin against severe group B streptococcal (GBS) infections. Whether the adjunct is important is of particular interest for elderly patients. Not only is the risk of aminoglycoside nephrotoxicity higher in elderly persons, but their immune defence to bacterial infections may also be impaired. METHOD: Time-kill assays with human blood products, such as serum, neutrophilic granulocytes (opsonophagocytic assays) and whole blood from healthy, elderly volunteers were performed to evaluate the effect of gentamicin in combination with penicillin...
October 21, 2016: Infectious Diseases
Kapil Tahlan, Marcus A Moore, Susan E Jensen
The δ-(L-α-aminoadipyl)-L-cysteinyl-D-valine (ACV) tripeptide is the first dedicated intermediate in the biosynthetic pathway leading to the penicillin and cephalosporin classes of β-lactam natural products in bacteria and fungi. It is synthesized nonribosomally by the ACV synthetase (ACVS) enzyme, which has been purified and partially characterized from many sources. Due to its large size and instability, many details regarding the reaction mechanism of ACVS are still not fully understood. In this review we discuss the chronology and associated methodology that led to the discovery of ACVS, some of the main findings regarding its activities, and some recent/current studies being conducted on the enzyme...
October 20, 2016: Journal of Industrial Microbiology & Biotechnology
Carla Novais, Ana P Tedim, Val F Lanza, Ana R Freitas, Eduarda Silveira, Ricardo Escada, Adam P Roberts, Mohammed Al-Haroni, Fernando Baquero, Luísa Peixe, Teresa M Coque
Ampicillin resistance has greatly contributed to the recent dramatic increase of a cluster of human adapted Enterococcus faecium lineages (ST17, ST18, and ST78) in hospital-based infections. Changes in the chromosomal pbp5 gene have been associated with different levels of ampicillin susceptibility, leading to protein variants (designated as PBP5 C-types to keep the nomenclature used in previous works) with diverse degrees of reduction in penicillin affinity. Our goal was to use a comparative genomics approach to evaluate the relationship between the diversity of PBP5 among E...
2016: Frontiers in Microbiology
Çiğdem Yılmaz, Gülay Özcengiz
The discovery of penicillin followed by streptomycin, tetracycline, cephalosporins and other natural, semi-synthetic and synthetic antimicrobials completely revolutionized medicine by reducing human morbidity and mortality from most of the common infections. However, shortly after they were introduced to clinical practice, the development of resistance was emerged. The decreasing interest from antibiotic industry in spite of rapid global emergence of antibiotic resistance is a tough dilemma from the pointview of public health...
October 17, 2016: Biochemical Pharmacology
Wesley D Oliver, Emily L Heil, Kerri A Thom, Joseph P Martinez, Bryan D Hayes
No abstract text is available yet for this article.
October 17, 2016: Journal of Allergy and Clinical Immunology in Practice
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